Methane-detector.



Patented June 26, 191?.

INVENTQFI JMMM,

CI IVI. MEANS.

METHANE DETECTOR.

APPLICATION FILED IAN.27, I9I6.

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WITNESSES .jf -Umani) sTATas PATENT OFFICE.

CHARLES M. MEANS, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR 0F TWO-THIRDS T0 WILLIAM A. MOCUTCHEON, 0F PITTSBURGH, PENNSYLVANIA.

METHANE-DETECTOR.

Specication ofLettcrs Patent.

Patented J une 26, 1917.

' To ZZ whom t may concern:

Be it known that I, CHARLES M. MEANS, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have 1nvented a new and useful Improvement in Methane-Detectors, of which the following is a specification.

This invention relates to a device for indicating or detecting the presence of eXplosive, iniammable, or otherwise dangerous gases, such as in mines, tunnels, sewers, buildings or othenplaces where dangerous conditions may exist because of the presence of gases. f The object of the invention is to provide a device for the purpose named which utilizes an electric current for the detection of such'gases. A further object of the invention is to provide a device for the purpose stated whereby within reasonable limits of accuracy the percentage of gas present can be determined. A further object of the invention is to provide a device of the character specified comprising a glower which is catalytically affected by the gas when heated, with the provision of means for restoring its catalytic properties in case of deterioration.

The invention comprises the combination and arrangement of parts hereinafter described and claimed.

The accompanying drawin shows a sectional view through the pre erred form -of the' device.

As illustrated, the detector comprises a ysuch as dry battery 3, and are preferably in series witheach other. As shown, one pole of the battery is connected through the conductor 4 with one endof the primary glower, while the other end of said primary glower is connected to the conductor 5,.to which conductor isalso connected one end of the secondary glower 2,"whose opposite end is connected through conductor 6 to the opposite pole of the battery 3. In'one of the conductors 4 or 6, as for instance in the conductor 6, is a switch7 for opening and closing said circuit. This switch is shown as a spring switch normally holding theJ circuit open and is arranged to close the circuit by means of a push button 8. The conductor 5 is connected through conductor 9 to the last named pole of the battery 3, and in this connection there is also a circuit opening and closing device, shown as a screw 10, which normally is open, and when closed serves to short circuit glower 2 for a purpose hereinafter described.

These elements may be made in a great variety of forms and may be variously arranged. They may be used in connection with the ordinary electric mine lamp, or with a separate battery, as shown, either primary or secondary. As illustrated, the conductors 4, 6 and 9 are embedded in an insulating `body 11, which in turn is inclosed in a casing 12, while the battery 3 is held in a casing 13 having a screw-threaded connection with -the casing 12, and having in its bottom a spring 111 for holding the battery 3 in firm contact with the terminal of conductor 4. The casings 12 and 13 are metallic and form the return path to the negative pole ofthe battery, and the switch 7 and short circuiting screw 10 have a conducting connection with casing 12.

, The glowing element or elements are preferably contained in a protecting chamber having gauze walls to permit the free circulation of air or gas therethrough but which will prevent an explosion or an ignition of the gases on the outside of the device in case of an explosion or ignition within the protecting ganzes, and which chamber is provided with a suitable window through which the glowing element or elements are visible. As illustrated, said glowers are inclosed in a chamber 15 formed by a transparent tube 16, such as a glass tube, and having its ends closed by protecting ganzes 17 and 18. Thesev gauzes each consist of three-ply wire gauze, and are clamped against the ends of the glass tube 16 by rings 19 and 20 respectively. The top ring 20 is provided wit a large central opening 21 while the bottom ring is provided with a plurality of smaller openings 22, as a result of which the air or gas can freely circulate through chambers 15. To prevent the entrance of gas anywhere except through the openings 22, the ring 19 has a close flt around the casing 12', while the insulating body 11 has a close lit in the interior of said casing and completely lls the same, and packing rings 23, such as asbestos, are interposed between the ends of the tube 16 and the rings 19 and 20. The several parts forming the walls of chamber l5 are held together by means of clamping bolts 24 passing through a top ring 25 resting on the ring 20 and a bottom ring 26 having a threaded connection with ring 19.

The material comprising the glowers 1 and 2 (or at least the glower 1) has a positive resistance coeiiicient, the resistance increasing as the temperature increases. The glower 1 has catalytic properties, that is, in the presence of gas its temperature and luminosity increase, while the glower 2 has no catalytic properties, and consequently in the presence of gas the luminosity of glower 2 is decreased due to the increased resistance of the circuit caused by the increased temperature of glower 1. The electric current serves to raise the temperature of the glowers to the point of luminosity, while the gas has the eii'ect of increasing the tempera- 1re and luminosity of the primary glower, which results in increasing its resistance, thus cutting down the amount of current flowing and decreasing the luminosity of the secondary glower.

The glowers are energized only at such times as tests for gas are actually being made. This is accomplished by closing the switch 7 to complete the circuit, which allows the current to flow through the two glowers in series. Ii2 there is no gas present both glowers will glow with the same intensity, but when brought in the presence of marsh or other gas the glower 1, due to its catalytic properties, will increase in temperature and luminosity, thereby increasing the resistance in thev circuit and cutting down the amount of current vflowing therethrough and proportionately decreasing the luminosity of glower 2. Consequently the presence of gas is indicated by a difference in temperature or luminosity of the two glowers, and the relative luminosities or temperatures of the two glowers indicate within reasonable limits of accuracy the percentage of gas present. In effect, the glower 2 serves as an indicating device to indicate the change of current iow in the circuit.

By closing the circuit of the conductor 9 by means of the screw 10 the secondary glower 2 is short circuited, and the current then passes only through the primary glower, thus producing a higher temperature of this glower and restoring its catalytic properties in case these have been lost or have deteriorated by use or because of the presence of a high percentage of moisture or other elements in the air which would cause said glower to deteriorate and lose its catalytic properties. By increasing the temperature of the glower to a proper point, these catalytic properties can be restored and this can be easily accomplished by merely short circuiting the secondary glower by means of screw 10.

The device is very easy and safe to use, and positively indicates the presence of gases, and, with reasonable accuracy, the percentage of gas in the air. The device is very simple and is always in working order, and as no current ows through the glower except when actually testing for gas, the current consumption is very small.

What I claim is 1. In a gas detector, a source of electric current, and two glowers located in proximity to. each other and in circuit with said sol source, one of said. glowers having catalytic properties and the other not having such properties, whereby the presence and amount of gas is detected by a comparison of the relative luminosities of vsaid glowers.

2. In a gas detector, a source of electric current, two glowers in circuit therewith, one of said glowers having catalytic properties and the other not having such properties, and a casing inclosing both glowers and arranged to admit gas-to said glowers.

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3. In a gas detector, a source of electric current, two glowers in series in circuit therewith, one of said glowers havingv a positive resistance co-eiiicient and the property that its temperature is increased in the presence of gas, thereby reducing'the current iiow through the second glower, ,said

second glower having the property that its temperature is unaiected by the presence of gas, and a casing inclosing said glowers and arranged to admit gas thereto.

4. In a gas detector, a source of electric current, two glowers in series in circuit therewith, one of said glowers havin catalytic properties and the other not aving such properties, and means in said circuit vforV causing increased current to flow through the glower having catalytic properties to restore said properties in case of deterioration.

5. In a gas detector, a source of electric current, two glowers in circuit therewith, one of said glowers being arranged to have its luminosity increased in the presence of gas and the other glower being arranged to be unaffected by the gas, and means for short circuiting the last named glower.

6. In a gas detector, a source of electric' current, a glower in circuit therewith and having catalytic properties, a .second re- In testimony whereof, I have hereunto sistance body in series with said glower, set my hand. and means for short circuiting said second body and thereby cause an increased current t CHARLES M' MEANS 5 from said source to ioW through said glower Witnesses:

\to restore its catalytic properties in case of y GLENN H. LERESCHE,

deterioration.

ELBERT L. HYDE. 

